videoQuality.minHeightForQualityLvl setting is not working for low quality level

Hi,

There is a videoQuality setting in config.js of the last stable release (4966).
When I set min height levels as the following, I never see low quality in the thumbnails.
Thumbnail resolutions are always shown as 427x240 (send max 180).

Am I missing something?

videoQuality: {
minHeightForQualityLvl: {
120: ‘low’,
240: ‘standard’,
480: ‘high’
}
}